diff -r 000000000000 -r 6474c204b198 dom/events/WheelEvent.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/events/WheelEvent.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,219 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/WheelEvent.h"
+#include "mozilla/MouseEvents.h"
+#include "prtime.h"
+
+namespace mozilla {
+namespace dom {
+
+WheelEvent::WheelEvent(EventTarget* aOwner,
+                       nsPresContext* aPresContext,
+                       WidgetWheelEvent* aWheelEvent)
+  : MouseEvent(aOwner, aPresContext,
+               aWheelEvent ? aWheelEvent :
+                             new WidgetWheelEvent(false, 0, nullptr))
+  , mAppUnitsPerDevPixel(0)
+{
+  if (aWheelEvent) {
+    mEventIsInternal = false;
+    // If the delta mode is pixel, the WidgetWheelEvent's delta values are in
+    // device pixels.  However, JS contents need the delta values in CSS pixels.
+    // We should store the value of mAppUnitsPerDevPixel here because
+    // it might be changed by changing zoom or something.
+    if (aWheelEvent->deltaMode == nsIDOMWheelEvent::DOM_DELTA_PIXEL) {
+      mAppUnitsPerDevPixel = aPresContext->AppUnitsPerDevPixel();
+    }
+  } else {
+    mEventIsInternal = true;
+    mEvent->time = PR_Now();
+    mEvent->refPoint.x = mEvent->refPoint.y = 0;
+    mEvent->AsWheelEvent()->inputSource = nsIDOMMouseEvent::MOZ_SOURCE_UNKNOWN;
+  }
+}
+
+NS_IMPL_ADDREF_INHERITED(WheelEvent, MouseEvent)
+NS_IMPL_RELEASE_INHERITED(WheelEvent, MouseEvent)
+
+NS_INTERFACE_MAP_BEGIN(WheelEvent)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMWheelEvent)
+NS_INTERFACE_MAP_END_INHERITING(MouseEvent)
+
+NS_IMETHODIMP
+WheelEvent::InitWheelEvent(const nsAString& aType,
+                           bool aCanBubble,
+                           bool aCancelable,
+                           nsIDOMWindow* aView,
+                           int32_t aDetail,
+                           int32_t aScreenX,
+                           int32_t aScreenY,
+                           int32_t aClientX,
+                           int32_t aClientY, 
+                           uint16_t aButton,
+                           nsIDOMEventTarget* aRelatedTarget,
+                           const nsAString& aModifiersList,
+                           double aDeltaX,
+                           double aDeltaY,
+                           double aDeltaZ,
+                           uint32_t aDeltaMode)
+{
+  nsresult rv =
+    MouseEvent::InitMouseEvent(aType, aCanBubble, aCancelable, aView, aDetail,
+                               aScreenX, aScreenY, aClientX, aClientY, aButton,
+                               aRelatedTarget, aModifiersList);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  WidgetWheelEvent* wheelEvent = mEvent->AsWheelEvent();
+  wheelEvent->deltaX = aDeltaX;
+  wheelEvent->deltaY = aDeltaY;
+  wheelEvent->deltaZ = aDeltaZ;
+  wheelEvent->deltaMode = aDeltaMode;
+
+  return NS_OK;
+}
+
+double
+WheelEvent::DeltaX()
+{
+  if (!mAppUnitsPerDevPixel) {
+    return mEvent->AsWheelEvent()->deltaX;
+  }
+  return mEvent->AsWheelEvent()->deltaX *
+    mAppUnitsPerDevPixel / nsPresContext::AppUnitsPerCSSPixel();
+}
+
+NS_IMETHODIMP
+WheelEvent::GetDeltaX(double* aDeltaX)
+{
+  NS_ENSURE_ARG_POINTER(aDeltaX);
+
+  *aDeltaX = DeltaX();
+  return NS_OK;
+}
+
+double
+WheelEvent::DeltaY()
+{
+  if (!mAppUnitsPerDevPixel) {
+    return mEvent->AsWheelEvent()->deltaY;
+  }
+  return mEvent->AsWheelEvent()->deltaY *
+    mAppUnitsPerDevPixel / nsPresContext::AppUnitsPerCSSPixel();
+}
+
+NS_IMETHODIMP
+WheelEvent::GetDeltaY(double* aDeltaY)
+{
+  NS_ENSURE_ARG_POINTER(aDeltaY);
+
+  *aDeltaY = DeltaY();
+  return NS_OK;
+}
+
+double
+WheelEvent::DeltaZ()
+{
+  if (!mAppUnitsPerDevPixel) {
+    return mEvent->AsWheelEvent()->deltaZ;
+  }
+  return mEvent->AsWheelEvent()->deltaZ *
+    mAppUnitsPerDevPixel / nsPresContext::AppUnitsPerCSSPixel();
+}
+
+NS_IMETHODIMP
+WheelEvent::GetDeltaZ(double* aDeltaZ)
+{
+  NS_ENSURE_ARG_POINTER(aDeltaZ);
+
+  *aDeltaZ = DeltaZ();
+  return NS_OK;
+}
+
+uint32_t
+WheelEvent::DeltaMode()
+{
+  return mEvent->AsWheelEvent()->deltaMode;
+}
+
+NS_IMETHODIMP
+WheelEvent::GetDeltaMode(uint32_t* aDeltaMode)
+{
+  NS_ENSURE_ARG_POINTER(aDeltaMode);
+
+  *aDeltaMode = DeltaMode();
+  return NS_OK;
+}
+
+static void
+GetModifierList(bool aCtrl, bool aShift, bool aAlt, bool aMeta,
+                nsAString& aModifierList)
+{
+  if (aCtrl) {
+    aModifierList.AppendLiteral(NS_DOM_KEYNAME_CONTROL);
+  }
+  if (aShift) {
+    if (!aModifierList.IsEmpty()) {
+      aModifierList.AppendLiteral(" ");
+    }
+    aModifierList.AppendLiteral(NS_DOM_KEYNAME_SHIFT);
+  }
+  if (aAlt) {
+    if (!aModifierList.IsEmpty()) {
+      aModifierList.AppendLiteral(" ");
+    }
+    aModifierList.AppendLiteral(NS_DOM_KEYNAME_ALT);
+  }
+  if (aMeta) {
+    if (!aModifierList.IsEmpty()) {
+      aModifierList.AppendLiteral(" ");
+    }
+    aModifierList.AppendLiteral(NS_DOM_KEYNAME_META);
+  }
+}
+
+already_AddRefed<WheelEvent>
+WheelEvent::Constructor(const GlobalObject& aGlobal,
+                        const nsAString& aType,
+                        const WheelEventInit& aParam,
+                        ErrorResult& aRv)
+{
+  nsCOMPtr<EventTarget> t = do_QueryInterface(aGlobal.GetAsSupports());
+  nsRefPtr<WheelEvent> e = new WheelEvent(t, nullptr, nullptr);
+  bool trusted = e->Init(t);
+  nsAutoString modifierList;
+  GetModifierList(aParam.mCtrlKey, aParam.mShiftKey,
+                  aParam.mAltKey, aParam.mMetaKey,
+                  modifierList);
+  aRv = e->InitWheelEvent(aType, aParam.mBubbles, aParam.mCancelable,
+                          aParam.mView, aParam.mDetail,
+                          aParam.mScreenX, aParam.mScreenY,
+                          aParam.mClientX, aParam.mClientY,
+                          aParam.mButton, aParam.mRelatedTarget,
+                          modifierList, aParam.mDeltaX,
+                          aParam.mDeltaY, aParam.mDeltaZ, aParam.mDeltaMode);
+  e->mEvent->AsWheelEvent()->buttons = aParam.mButtons;
+  e->SetTrusted(trusted);
+  return e.forget();
+}
+
+} // namespace dom
+} // namespace mozilla
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+nsresult
+NS_NewDOMWheelEvent(nsIDOMEvent** aInstancePtrResult,
+                    EventTarget* aOwner,
+                    nsPresContext* aPresContext,
+                    WidgetWheelEvent* aEvent)
+{
+  WheelEvent* it = new WheelEvent(aOwner, aPresContext, aEvent);
+  NS_ADDREF(it);
+  *aInstancePtrResult = static_cast<Event*>(it);
+  return NS_OK;
+}